1. Field of the Invention
The present invention relates to a feeder for supplying a weft to a weaving machine having no reed, such as a rapier type weaving machine.
2. Description of the Prior Art
Generally, in this type of weaving machine or loom, the size of a weft-wound ball from which weft is fed to the weaving machine decreases as the weft is consumed. Correspondingly, the pull or draw-out tension varies as the weft-wound ball reduces in diameter. Therefore, a feeder is required to feed the weft to the weaving machine so as to maintain a constant feeding tension of the weft.
One weft feeder of this type is disclosed in Japanese Patent Laid-Open Publication No. 60-259654. In this weft feeder, as shown in FIG. 14 hereof, a weft Y is wound about a drum 10 by means of a rotary reel or flyer 14. The wound weft Y is advanced by the action of a carrier 23, which extends and retracts from an outer peripheral surface of the drum 10. A base portion 5 of the carrier 23 is rotatably attached to a bushing 7, which is eccentrically fitted and secured to a drum shaft. The axis center of the base portion 5 is inclined with respect to the drum shaft 13. The drum 10 and the carrier 23, however, do not rotate. Accordingly, when the bushing 7 is rotated together with the drum shaft 13, the carrier 23, which is rotatably attached to the bushing 7 through the base portion 5, is oscillated back and forth, as shown by the broken lines. While the carrier 23 is protruding and retracting from the surface of the drum 10, depending on the angle of inclination and the amount of eccentricity of the bushing 7, the carrier 23 operates to advance the weft Y off the front of the drum 10.
A problem occurs where the weft is a nylon twisted yarn having substantially no nap. The weft fed to the weaving machine is naturally twisted. Therefore, it is necessay to reverse the direction of winding, depending on the direction of twisting of the weft, i.e., Z-twisting or S-twisting. Specifically, it is always necessary when feeding the weft to wind the warp not in the direction in which the twist is released, but rather in the direction in which the twist is tightened. To attain this, it is necessary to change the direction of inclination of the bushing 7.
In this known feeder, it is inconvenient to change the inclination of the bushing 7. The setting and changing of the weft-feeding pitch, and the setting and changing of the direction of movement of the carrier, with respect to the direction of rotation of the flyer, cannot be accomplished without disassembling the feeder.
In a weft feeder of this known type, and as shown in FIG. 15, sensor members 41 are provided that are pivotably supported within slits formed radially from the inside of the drum 10. A bearing member 41a pivotably supports each sensor member 41. Each sensor member 41 extends outwardly from each slit beyond the surface of the drum 10. One sensor member detects the presence of weft wound about the base portion of the drum 10. The second sensor member detects the amount of weft feeding past the flyer.
A coil spring 83 is used as a biasing spring for making a part of each sensor member 41 protrude above the outer surface of the drum 10. Generally, in the case of the coil spring 83, a certain load is necessary to supply tension until the coil spring 83 begins expansion. Since the coil spring 83 has its own weight, a first side 41c of the sensor member 41 is made heavier than a second side 41b, so that balance is achieved about the fulcrum 41a. Any response is slow due to the action of the moment of inertia. The detection of the weft with a light touch, as light as 0.5 g or less, is impossible. Furthermore, a malfunction sometimes occurs due to the deposition of dust, down or weft between the coils of the coil spring 47. Such situations are undesirable.
Furthermore, in the weft feeder of this type, the flyer stops when winding the weft about the drum 10 is finished. The flyer restarts supplying the weft when the residual quantity of weft is reduced. Thus, after the motor is decelerated by inverter control, the flyer will ultimately stop. As a result, a characteristic of the flyer decelerating and stopping is noted; specifically, the flyer rotates to a small extent in a reverse direction before stopping. This is due to the tension in the weft.
This characteristic of the flyer driving system sometimes causes a serious problem. A defect, independent of the direction of twist of the weft, occurs with respect to the tension applied to the weft. More specifically, in supplying the weft to the drum, the direction the weft is wound and the tension of feeding of the weft are controlled so that a natural twist is always applied to the weft. However, when the flyer is rotated in a reverse direction, the force restricting the twisting of the weft does not act anymore. As shown in FIG. 13B, a torsion phenomenon is caused in which a part of the weft is folded and twisted, as compared with a normal state shown in FIG. 13A. The weft, having such a twisted portion, is seldom restored to its original state. If a considerable tension is applied to the weft to restore the original state, the strength of this portion of the weft is significantly degraded. Accordingly, when the flyer is restarted, the degraded weft is fed to a weaving machine. The woven cloth manufactured with this degraded weft will have this a defect therewithin. Alternatively, the weft could break at the degraded portion, causing a malfunction in the weaving machine.